Cardiac Glycosides in Partly Submerged Shoots ofDigitalis lanata*

Abstract

Shoot cultures were established from axillary buds (11 strains) or seeds (1 strain) of individual Digitalis lanata Ehrh. plants and propagated partially submerged in liquid medium. Five of these shoot culture strains were characterized with regard to their growth and cardenolide content. The cultures were observed for more than one year and found to be relatively stable with regard to their growth and cardenolide spectrum and yield. The strains examined differed in terms of their total cardenolide yield, which ranged from about 30 nmol g DW-1 to almost 1000 nmol g DW-1. Cardenolide content was correlated with leaf size and development. Depending on the strain investigated up to ten different cardenolides could be detected by HPLC. The main cardenolides were identified by comparing HPLC and TLC results with those of authentic samples and chemical degradation as being the mono- and diglycosides glucodigifucoside, glucoverodoxin, odorobioside G, and odoroside H; minor amounts of digitalinum verum and glucoevatromonoside were also found. In addition, the tetrasaccharides lanatoside A and C were present. The shoots were cardenolide-free when cultivated in the dark for more than 30 weeks, but regained their characteristic cardenolide profile when transferred back to light. For the dark cultivation of chlorophyll-free cultures a medium containing 3.5% glucose was found to be optimal.

Uptake, Transport and Storage of Cardenolides in Foxglove. Cardenolide Sinks and Occurrence of Cardenolides in the Sieve Tubes of Digitalis lanata1

“…Axenic plantlets. Axenic plantlets were obtained from the shoot culture D (Stuhlemmer et al, 1993). Root formation was induced on agar-solidified W 92 medium (containing 2 mg indolylbutyric acid) as described by Schoner and Reinhard (1986).…”

“…Axillary buds were prepared and cultivated in liquid medium as described by Schoner and Reinhard (1986) and established as a continuous, partly submerged, mixotrophic shoot culture without roots. The shoots were grown in 300 ml Erlenmeyer flasks containing 50 mlliquid modified MS (Murashige and Skoog, 1962) medium (Stuhlemmer et al, 1993). The flasks were kept on a gyratory shaker (80 rpm, 24°C; RC 1 TK Infors, Munchen, Germany) under continuous light (3800 lux on the shaker plate, L18W/25 Osram, Munchen, Germany).…”

Effects of Various Pregnanes and Two 23-Nor-5-cholenic Acids on Cardenolide Accumulation in Cell and Organ Cultures ofDigitalis lanata

“…gnane-modifying enzymes. The administration of pregnenolone and progesterone to cultured D. lanata shoots caused the accumulation of 5 a-pregnanes, whereas 5$-pregnanes could not be detected (19). The enzyme responsible for this conversion, termed progesterone 5a-reductase, was described recently (30) and it was hypothesized that it may remove precursors from the cardenolide pathway.…”

Cardiac glycosides from shoot cultures ofCryptostegia grandiflora

“…callus and cell suspension cultures[9–13] can be offered alternative sources for large scale production of cardiac glycosides.…”